I don't run a negative ground radio in a positive ground car, but in years past
I did convert a few CB and AM/FM radios for semi trucks. Many of which were
positive ground at the time.
To do this I had to locate each and every ground point on the printed circuit
board and make sure that it was separated from any mounting screw or other
attachment to the chassis. The opening left after cutting the circuit board
foil was bypassed by a small capacitor to chassis ground and jumpers added to
restore ground circuits that may have been broken. Once all of these points
have been found and rejoined a positive and a negative wire are brought out of
the now isolated radio case. Make sure you install a polarity diode in series
with one of these wires to guard against incorrect power connection, use an
ohmmeter to confirm that there is no connection from the chassis to either power
wire, and you are done.
I have not worked on a newer car radio for many years. With the increasingly
tight component packaging, and possibly multi-layer circuit boards, I don't know
if you can go through all of that described above or not. Back then some radios
were designed to go in either way from the start.
I think your best solution is to either live with the original radio as long as
it is transistorized, or convert the car to negative ground and make it easy to
deal with in today's world.
Tom
69 2000
Portland, Oregon
Dan Zubkoff wrote:
> You are right...~10 years ago Radio Shack used to sell one of these
> converter/inverters, however they are NLA.
>
> All the new radios made are 12v negative ground. When you go to most car
> audio shops, they don't have a clue as to what they (the converter/inverter)
> are or where to buy them.
>
> Question: Is anyone out there running a 12v negative ground radio in a
> positive ground car?
>
> Dan Zubkoff
> San Mateo, CA
>
> >From: "Patrick J. Horne" <horne@cs.utexas.edu>
> >Reply-To: "Patrick J. Horne" <horne@cs.utexas.edu>
> >To: Dan Zubkoff <datsun65@hotmail.com>
> >CC: <Daniel@nowroc.com>, <datsun-roadsters@autox.team.net>
> >Subject: Re: 64 vs. 66
> >Date: Fri, 4 Oct 2002 12:48:25 -0500 (CDT)
> >
> >Positive ground radios shouldn't be a big problem, at least they weren't
> >several years ago. When most cars went to 12V negative ground there were
> >still plenty of cars with 6V negative ground and 12V positive ground
> >around There was an adapter (DC to DC converter) that could be set to
> >convert either 6V negative ground or 12V positive ground to 12V negative
> >ground. I haven't looked for one of these in many years, but there should
> >be a source for them. With this converter installed you can install any
> >12V negative ground accessory you like!
> >
> >Peace,
> >Pat
> >
> > - Support Habitat for Humanity, A "hand up", not a "hand out" -
> >
> >Pat Horne, Network Manager, Shop Supervisor/Future planner, CS Dept,
> >University of Texas, 1 University Station C0500,Austin, Tx. 78712-1188 USA
> >voice (512)471-9730, fax (512)471-8885, horne@cs.utexas.edu
> >
> >On Fri, 4 Oct 2002, Dan Zubkoff wrote:
> >
> > > Hi Daniel,
> > >
> > > I have both a 64 and a 66....
> > >
> > > The 64 has drum brakes all the way around and uses 6 wheel cylibders (4
> > > front & two back)and a different brake master and hoses than the 66. The
> > > master is NLA, but there is another unit (I think from a 411) that will
> >work
> > > instead. The brake parts are hard to come by...
> > >
> > > The rear end has a lower gear ratio than the 66. Also, the 64 is a
> >positive
> > > ground car and the 66 is negative ground. Good luck in trying to find a
> > > replacement positive ground radio!!! Also, the 64 uses 13 inch rims, not
> >14
> > > inch like the later cars.
> > >
> > > Also, the top of the windshield frame and the soft top frame are
> >different.
> > > The front bow on the top frame is made of wood!
> > >
> > > In general, parts are harder to come by for the 1500s, but the early
> >cars
> > > are just a blast to drive & own!
> > >
> > > Dan Zubkoff
> > > San Mateo, CA
> > > 1964 SPL310 1500
> > > 1966 CSP311 Silvia
> > > 1966 SPL311 1600
> > >
> > >
> > > >From: "Daniel Beatty" <Daniel@nowroc.com>
> > > >Reply-To: "Daniel Beatty" <Daniel@nowroc.com>
> > > >To: "Roadsters" <datsun-roadsters@autox.team.net>
> > > >Subject: 64 vs. 66
> > > >Date: Fri, 4 Oct 2002 00:50:49 -0700
> > > >
> > > >G'day,
> > > >
> > > >
> > > >
> > > >I sent this to the list today, but it never appeared so I will try
> > > >again.
> > > >
> > > >
> > > >
> > > >What are the differences between the 64 and the 66 other than engine
> > > >size, exterior and interior? I thought that there were differences in
> > > >the chassis and some other bits. Are there special things that I
> >should
> > > >look for in a 64 that I am thinking of buying? Are all parts as
> >readily
> > > >available as the later model Roadsters?
> > > >
> > > >
> > > >
> > > >Anyone on the list have a 64??
> > > >
> > > >
> > > >
> > > >Cheers,
> > > >
> > > >Daniel Beatty
> > > >
> > > >RHD 65.5 1600
> > > >
> > > >/// datsun-roadsters@autox.team.net mailing list
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> > > >/// Archives at http://www.team.net/archive
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> > >
> > >
> > >
> > >
> > > _________________________________________________________________
> > >
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